128k views
5 votes
3. 3x + 4y = 8 x=16-4y

User SirKnigget
by
7.7k points

1 Answer

6 votes
Solving a system of equations

We want to find where x and y are equal in both equations.

First step: replacing the x value given by the second equation in the first

3x + 4y = 8

x = 16 - 4y​

3(16 - 4y​) + 4y = 8

Distributing the parenthesis:

3 · 16 - 3 · 4y + 4y = 8

48 - 12y + 4y = 8

48 - 8y = 8

Rearranging the equation:

48 - 8y = 8

48 - 8 = 8y

40 = 8y

40/8 = y

5 = y

Second step: replacing the 5 = y value in one of the equations

We replace it in the second equation:

x = 16 - 4y​

x = 16 - 4 · 5

x = 16 - 20

x = -4

Solution: y = 5 amd x = -4

User Ben Toh
by
7.4k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories